This invention relates to profiled, bead and recess fasteners, such as may be made by extrusion of plastics material to substitute for the slide type fastener with interlocking teeth attached to stringers that can be sewn to edges e.g. of garments required to be releasably joined. Such profiled fasteners are to be found on plastic document wallets.
It is a problem with such fasteners that, largely on account of the flexible nature of the material of which they are made, they are relatively easy to spring open. To provide greater resistance against such springing open, while leaving the fastener easy to open intentionally, more complicated cross sectional latching arrangements have been proposed. These, however, require correspondingly complicated sliders. While such complicated sliders are realisable theoretically, in practise it is difficult, if not impossible, to produce them easily and inexpensively to the right tolerances, especially in the smaller sizes of fastener.